tokio: add AsyncReadExt::read_to_end (#1279)

1 files changed, 40 insertions, 0 deletions

diff --git a/tokio/tests/io_read_to_end.rs b/tokio/tests/io_read_to_end.rs
new file mode 100644
index 00000000..ac089625
--- /dev/null
+++ b/tokio/tests/io_read_to_end.rs
@@ -0,0 +1,40 @@
+#![deny(warnings, rust_2018_idioms)]
+#![feature(async_await)]
+
+use tokio::io::{AsyncRead, AsyncReadExt};
+use tokio_test::assert_ok;
+
+use std::pin::Pin;
+use std::task::{Context, Poll};
+use std::{cmp, io};
+
+#[tokio::test]
+async fn read_to_end() {
+    struct Rd {
+        val: &'static [u8],
+    }
+
+    impl AsyncRead for Rd {
+        fn poll_read(
+            mut self: Pin<&mut Self>,
+            _cx: &mut Context<'_>,
+            buf: &mut [u8],
+        ) -> Poll<io::Result<usize>> {
+            let me = &mut *self;
+            let len = cmp::min(buf.len(), me.val.len());
+
+            buf[..len].copy_from_slice(&me.val[..len]);
+            me.val = &me.val[len..];
+            Poll::Ready(Ok(len))
+        }
+    }
+
+    let mut buf = vec![];
+    let mut rd = Rd {
+        val: b"hello world",
+    };
+
+    let n = assert_ok!(rd.read_to_end(&mut buf).await);
+    assert_eq!(n, 11);
+    assert_eq!(buf[..], b"hello world"[..]);
+}